我想要一个MenuItem(在“About”)的功能,如“File”菜单.

package model;

import static java.lang.System.out;

import javafx.application.Application;
import javafx.beans.property.ReadOnlyDoubleProperty;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.geometry.Side;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyCodeCombination;
import javafx.scene.input.KeyCombination;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

/**
 * Example of creating menus in JavaFX.
 * 
 * @author Dustin
 */
public class JavaFxMenus extends Application
{
   /**
    * Build menu bar with included menus for this demonstration.
    * 
    * @param menuWidthProperty Width to be bound to menu bar width.
    * @return Menu Bar with menus included.
    */
   private MenuBar buildMenuBarWithMenus(final ReadOnlyDoubleProperty menuWidthProperty)
   {
      final MenuBar menuBar = new MenuBar();

      // Prepare left-most 'File' drop-down menu
      final Menu fileMenu = new Menu("File");

      menuBar.getMenus().add(fileMenu);
      //menuBar.getOnMouseClicked().handle(this);


      // Prepare 'Examples' drop-down menu
      final Menu examplesMenu = new Menu("JavaFX 2.0 Examples");
      examplesMenu.getItems().add(new MenuItem("Text Example"));
      examplesMenu.getItems().add(new MenuItem("Objects Example"));
      examplesMenu.getItems().add(new MenuItem("Animation Example"));
      menuBar.getMenus().add(examplesMenu);

      // Prepare 'Help' drop-down menu
      final Menu helpMenu = new Menu("Help");
      helpMenu.setOnAction(null);

      final MenuItem searchMenuItem = new MenuItem("Search");
      searchMenuItem.setDisable(true);
      helpMenu.getItems().add(searchMenuItem);
      final MenuItem onlineManualMenuItem = new MenuItem("Online Manual");
      onlineManualMenuItem.setVisible(false);
      helpMenu.getItems().add(onlineManualMenuItem);
      helpMenu.getItems().add(new SeparatorMenuItem());
      final MenuItem aboutMenuItem =
         MenuItemBuilder.create()
                        .text("About")
                        .onAction(
                            new EventHandler<ActionEvent>()
                            {
                               @Override public void handle(ActionEvent e)
                               {
                                  out.println("You clicked on About!");
                               }
                            })
                        .accelerator(
                            new KeyCodeCombination(
                               KeyCode.A,KeyCombination.CONTROL_DOWN))
                        .build();             
      helpMenu.getItems().add(aboutMenuItem);
      menuBar.getMenus().add(helpMenu);

      // bind width of menu bar to width of associated stage
      menuBar.prefWidthProperty().bind(menuWidthProperty);

      return menuBar;
   }

   /**
    * Start of JavaFX application demonstrating menu support.
    * 
    * @param stage Primary stage.
    */
   @Override
   public void start(final Stage stage)
   {
      stage.setTitle("Creating Menus with JavaFX 2.0");
      final Group rootGroup = new Group();
      final Scene scene = new Scene(rootGroup,800,400,Color.WHEAT);



      final MenuBar menuBar = buildMenuBarWithMenus(stage.widthProperty());
      rootGroup.getChildren().add(menuBar);
      stage.setScene(scene);
      stage.show();
   }

   /**
    * Main executable function for running examples.
    * 
    * @param arguments Command-line arguments: none expected.
    */
   public static void main(final String[] arguments)
   {
      Application.launch(arguments);
   }
}